When to recharge Li Time 100Ah mini lifep04 battery

[NVS]

That's ok you'll probably never see 10amps due to line loss. Let it charge until you see 0 amps of charge or relatively close to 0 amps. At that point hopefully your close to 14.6v but after a few hours your battery will rest or float at around 13.6v.

I guess as long as you are getting 100ah out of your battery it's fine. I would still drain it until the bms shuts off then recharge it to full just to make sure your shunt meter is set right.

 

[Tomthumb62]

Actually, the Li Time 10A charger only seems to charge at 13.4v for some reason, and not more than 9.87A as it's a 10A charger. I asked Li Time why it was only 13.4v instead of 14.6v, they just said "it is ok".

The charge cycle is aimed to eventually reach 14.6v. It will charge at a constant current (10A or so) until it reaches 14.6v. If you aren’t there with a multimeter right at the moment it reaches 14.6v, you’ll miss it.

How much time you have before you miss it depends upon how the charge cycle is set for the charger. You could ask LiTime how long the absorption period is set for. If it’s long like 2 hours then you have a better chance of seeing 14.6v. But if it’s short or set to zero, it will be harder to catch.

What I love about my Victron IP22 charger is the app it works with will show you the charge history and exactly how long it spent in each section and what voltage it reached. No need to sit there waiting with a multimeter.

 

[400bird]

So there's no threshold that I should never let it fall below?

The individual cells should never go below 2.5 volts. You cant measure th cells, so you must rely on the BMS to do it's job and protect them. The answer to your question is basically yes. Some cell manufacturers increase the rates cycle count from 3,000 to 5,000 (or whatever arbitrary numbers they've decided on) if you stay above 20%
But even with daily cycling, 3,000 cycles is 8 years. You aren't doing cycles daily, so the chemical reaction in the cells might last a decade or longer for you. However, the rest of the battery probably won't. This is why people talk about the battery aging out, the BMS, plastic case, something else is likely to fail before the cells.
Also, the SOC will slowly drift and loose accuracy and need a full charge to reset, so don't let it sit for weeks and think you can run it down to 2%, the SOC might be 13% off from reality.

All this complication is why most just ?‍ and charge whenever they can and why I recommend not overthinking it.

I'm checking thr voltage worh my meter as it's charging yes, and it doesn't charge more than 13.4v@ 9.86A with the Li time charger.

As was already said, you'd have to sit there and monitor the voltage for the entire charge and it very slowly rises for 90% of the charge time then quickly spikes up near the end of charge. Then will drift back down after the charge is complete.

Try leaving the meter connected with the min/max active. That is if you can keep the meter from falling asleep.

 

[mikefitz]

Renogy battery monitor settings:
-Capacity - 100Ah
-Full - 13.33v

The 'Full' setting at 13.33 volts is incorrect. The battery needs to reach a voltage over 13.4, idealy about 0.1 volts lower than the charger absorbtion volts. Due to thus low setting you are seeing odd results in SOC. 14.0 volts would be a reasionable value to use.

Even that Amazon charger only charges at 14.1v max, and at 15 to 16 amps

That's OK, even 13.8 volts will charge to full given time. Charging to 14.6 volts is impossible on low cost batteries, as the cell inbalance will cause the BMS to stop charging well before the battery reaches 14.6 volts. Charging to 14.6 volts is unnecessary and causes more harm that good. 14.0 to 14.2 volts absorbtion and 13.5 volts float are useful charge voltages.

just want to know at what point when I run the battery down do I recharge it again.

Idealy you want to keep above 20% SOC, that's 13.0 volts on a rested battery, ( no load or charge). Your Renogy monitor should, ( once correctly set up) give an indication of SOC. It's OK operating at partial state of charge, say 40% to 80%, but a charge to over 13.8 volts is needed regularly to keep the cells in balance.

 

[Bluenoser316]

The 'Full' setting at 13.33 volts is incorrect. The battery needs to reach a voltage over 13.4, idealy about 0.1 volts lower than the charger absorbtion volts. Due to thus low setting you are seeing odd results in SOC. 14.0 volts would be a reasionable value to use.

That's OK, even 13.8 volts will charge to full given time. Charging to 14.6 volts is impossible on low cost batteries, as the cell inbalance will cause the BMS to stop charging well before the battery reaches 14.6 volts. Charging to 14.6 volts is unnecessary and causes more harm that good. 14.0 to 14.2 volts absorbtion and 13.5 volts float are useful charge voltages.


Idealy you want to keep above 20% SOC, that's 13.0 volts on a rested battery, ( no load or charge). Your Renogy monitor should, ( once correctly set up) give an indication of SOC. It's OK operating at partial state of charge, say 40% to 80%, but a charge to over 13.8 volts is needed regularly to keep the cells in balance.

This is straight from the Li Time battery manual for my battery, and Li Time themselves told me that it should rest at 13.33v, and then it is fully charged several times when I asked them. This is why I am confused.

 

[mikefitz]

Li Time themselves told me that it should rest at 13.33v, and then it is fully charged

True, resting voltage will be 13.4 volts +/- 0.05 volts, but when charging, the charge voltage has to be higher than battery 'internal volts'.
So to allow the battery monitor to sync to 100% you need to set 'full' to a higher value, usually slightly lower than the charger absorbtion voltage.

Voltage sits at 13.28v when I turn off the radios. This all seems normal as the battery is slowly and lightly being drained by running the radios all day.
The next morning, I look at my battery monitor, and the Ah is 99Ah, the percent left is back up to 100%, and the time left is 99:59 again!
What's going on here?

Once the load is removed the battery volts will recover a little. 13.28 is not much lower than 13.33 and the Renogy unit can only be set to one decimal place, ( and only display voltages values to one decimal place). Add in rounding up or down errors and its easy to see that the monitor will reset to near 100%, based on a 'full' volts of 13.3.

Try setting the 'full' volts to a higher value, achieved by your chargers, example 14.0 volts.

 

[Bluenoser316]

True, resting voltage will be 13.4 volts +/- 0.05 volts, but when charging, the charge voltage has to be higher than battery 'internal volts'.
So to allow the battery monitor to sync to 100% you need to set 'full' to a higher value, usually slightly lower than the charger absorbtion voltage.

Once the load is removed the battery volts will recover a little. 13.28 is not much lower than 13.33 and the Renogy unit can only be set to one decimal place, ( and only display voltages values to one decimal place). Add in rounding up or down errors and its easy to see that the monitor will reset to near 100%, based on a 'full' volts of 13.3.

Try setting the 'full' volts to a higher value, achieved by your chargers, example 14.0 volts.

Thanks for taking the time to reply. You'd never guess that I'm a retired electronics technician. Unfortunately I've suffered a past brain injury and am now disabled, also with Ehlers-Downlos Syndrome, so my memory has suffered. Anyhow, I've set the battery full value to 14v in the Renogy battery monitor as you suggested. I recharged the battery with the 20A Amazon charger this time, and the charge Amps vary throughout the cycle, it did at one point reach a full 20A, but mainly charged at around 15.6A.
So, the voltage on the charger says 14.4v maximum, but mostly charging at 14.1v, and at the same time I measure 13.55v with my very accurate multimeter. At the same time, the Renogy battery monitor says it is charging at 13.5v. Lol.
Once it was finished charging, the voltage read as 13.66v.
I let it rest for 3 hours, and it fell to 13.33v as it always does.
Now, I've been running my radio from it for a couple hours at about an amp continous, and it now measures as 13.31v.
Does all this sound normal to you?
I don't know why so many people keep telling me that the battery should charge at 14.6v. And actually be measured at 14.5v ect once fully charged. Is there something different about this LiTime 100Ah lifep04 Mini battery?
If I were to charge it with the Li time 10A AC wall charger instead of tge Haisito 20A charger, the end results would be the same, 13.33v after resting, but, it would only charge at 13.4v @ 9.84A.

I'm sorta torn about what charger I should really be using. The Li Time 10A charger is clearly a better quality charger, being all metal construction ect, but it's only 10A, while the amazon Haisito charger is 20A, and seems to charge at a higher voltage as well. The amazon Haisito 20A charger is noisy, the fan is loud and runs continuously, but the Li Time 10A charger has no fan, and is silent, and runs relatively cool.

 

[Brucey]

I have four Redodo 12V 100Ah minis. I just run them until the BMS shuts it off. Then I recharge it with an IP22 12/30 at 15A at 14.2V.

 

[Tomthumb62]

I don't know why so many people keep telling me that the battery should charge at 14.6v. And actually be measured at 14.5v ect once fully charged. Is there something different about this LiTime 100Ah lifep04 Mini battery?

I agree, it's very confusing. It's the cost of free advice on this forum, lol. You have to know who to listen to and who to ignore. And some people I ignore some of their advice and accept other things they say at another time. Lol!

First, the voltage will drop very quickly from whatever voltage it topped out at. Within seconds or minutes. It will not hang out above 13.4 (on a full battery) for very long at all.

Second, while in theory it should reach 14.6v, very very often LiFePO4 will never reach the target voltage. Why? Because the BMS cuts out charging early, due to usually one cell being higher voltage than the others. This happens with usually the cheap batteries like LiTime but even expensive batteries are sometimes out of balance. In order for that single cell to not get over-charged/damaged, the whole battery suffers and thus the actual ending voltage may be as bad as 13.8v (or lower if REALLY out of balance) but usually 14.0-14.4 is common.

So, long story short, it sounds like your charger is working properly and your battery is receiving a proper charge. If you wish it to be better balanced, you probably need a new charger than can be programmed like the Victron IP22 series or a bench power supply can work too, the bench supply requires much more babysitting. Or you can ask LiTime if the charger you have from them is capable of balancing your battery.

 

[Bluenoser316]

I agree, it's very confusing. It's the cost of free advice on this forum, lol. You have to know who to listen to and who to ignore. And some people I ignore some of their advice and accept other things they say at another time. Lol!

First, the voltage will drop very quickly from whatever voltage it topped out at. Within seconds or minutes. It will not hang out above 13.4 (on a full battery) for very long at all.

Second, while in theory it should reach 14.6v, very very often LiFePO4 will never reach the target voltage. Why? Because the BMS cuts out charging early, due to usually one cell being higher voltage than the others. This happens with usually the cheap batteries like LiTime but even expensive batteries are sometimes out of balance. In order for that single cell to not get over-charged/damaged, the whole battery suffers and thus the actual ending voltage may be as bad as 13.8v (or lower if REALLY out of balance) but usually 14.0-14.4 is common.

So, long story short, it sounds like your charger is working properly and your battery is receiving a proper charge. If you wish it to be better balanced, you probably need a new charger than can be programmed like the Victron IP22 series or a bench power supply can work too, the bench supply requires much more babysitting. Or you can ask LiTime if the charger you have from them is capable of balancing your battery.

Thanks for your reply ?.
I'm pretty good at figuring out who is giving me bad information lol. FB is even worse for this. My expectation is that someone with "actual" experience will give me some guidance based on "actual" experience lol.
I'm not too demanding on this battery system. I simply want to charge it, use it, and recharge it again. And get on a proper "cycle" of doing so, as I'm doing it all manually for now. Maybe one day when I can get solar hooked up things will change, but for now, I just want a method of using this system based on logic and experience from others. It's like this, I run my ham radios from the battery, straight DC from the battery, I recharge it when I'm "supposed" to, and then, repeat, day after day. DC power is much cleaner for radio use, rather than the noisy apartment wall power that is quite noticeable, so having my radio already running on backup if the power goes out is a bonus, as well as a cleaner power source.
In addition to this, I have the Renogy 1000w pure sine wave inverter that can be connected and used for AC appliances like my freezer ect for power outages, and that's really the full scope of this battery backup usage. Nothing major.
Funny thing is after all this I'm still not truly sure "exactly" when to recharge the battery, as I've had so many answers lol.
From what I've read, I should let it run down to 20%-50% charge left before I recharge it, or, according to others, i should charge it daily because it actually really doesn't matter lol. One person asked why I don't just leave the charger connected and running at all times. The answer to that is simple, I don't trust it, as its in my bedroom, and i keep a close watch on it, and, it's very noisy for the ham radio. I don't use the radio at the same time it is charging. Thanks again for your help.

 

[Tomthumb62]

One person asked why I don't just leave the charger connected and running at all times. The answer to that is simple, I don't trust it, as its in my bedroom, and i keep a close watch on it,

Yeah I wouldn’t trust that charger either. It’s probably fine but hey it’s LiTime after all. LiTime’s selling point is their low price. Will Prowse continues to vouch for them because they just don’t seem to have many problems and are easy try warranty if they happen to fail the QC team. They do have problems that about 80% of LFP have - poorly balanced cells. Which should get balanced over time with a decent charger.

With a programmable charger like the Victron IP22, you can safely leave the charger connected 24/7, once programmed properly. But I would want to know the nitty gritty details of your LiTime charger before doing that.

 

[Bluenoser316]

Yeah I wouldn’t trust that charger either. It’s probably fine but hey it’s LiTime after all. LiTime’s selling point is their low price. Will Prowse continues to vouch for them because they just don’t seem to have many problems and are easy try warranty if they happen to fail the QC team. They do have problems that about 80% of LFP have - poorly balanced cells. Which should get balanced over time with a decent charger.

With a programmable charger like the Victron IP22, you can safely leave the charger connected 24/7, once programmed properly. But I would want to know the nitty gritty details of your LiTime charger before doing that.

Not sure what there is to say about this charger, it's a 10A charger with zero settings, you connect it, it turns red when it's charging, and green when it's done. It's the exact same model number that I've seen on a number of other brand name chargers, same one, different brand name on the box, same model number on the charger. I've seen it under Power Queen, Eco worthy, ect.

Yeah I wouldn’t trust that charger either. It’s probably fine but hey it’s LiTime after all. LiTime’s selling point is their low price. Will Prowse continues to vouch for them because they just don’t seem to have many problems and are easy try warranty if they happen to fail the QC team. They do have problems that about 80% of LFP have - poorly balanced cells. Which should get balanced over time with a decent charger.

With a programmable charger like the Victron IP22, you can safely leave the charger connected 24/7, once programmed properly. But I would want to know the nitty gritty details of your LiTime charger before doing that.

I let my battery go down to 89%, and since we have a major wind and rain storm coming tomorrow (we are sure to lose power) I decided to charge the battery.
I used the Haisito 20A charger to charge it, and watched it charge. I measured it with my multimeter as it charged, and also observed the charger voltage display and the Renogy battery monitor display to compare the voltage values.

It started out charging at 13.7v according to the multimeter, but the charger voltage read 14.1v.
The current according to the charger started out at 15.4A.
As it charged, the current never increased past 15.2A, but in the past, it's charged up to a full 20A. Not sure why this time it remained around 15A during charging the whole time.
Anyhow, the voltage slowly increased throughout the charging, from 13.7v to 13.9v, then right near the end, I watched the voltage slowly creep up to 14.14v for only a few moments, then, it was full, and the charger shut down.
This is the 1st time I observed the voltage increase at the end like that, and I was at least happy to see that it did get to over 14.1v, as measured on the actual multimeter, not what is shown on the charger display. Why are the 2 values always different? When the multimeter finally showed 14.14v at the end of the charge cycle right before shutting off, the charger showed 14.6v on the charger display.
The Renogy battery monitor did seem to accurately show the same voltage as the multimeter at least, but of course the battery monitor only has one decimal point voltage display.
So, I "guess" it's charging correctly, and if only for a short moment, the charge voltage does seem to get to above 14v.
I'm guessing that the difference in how the battery is charging this time is due to the cells balancing as you mentioned?
Can i expect the battery voltage and current to change while charging to different values each time I charge the battery ad the cells level out?
Thanks again in advance for your replies.

 

[Tomthumb62]

As it charged, the current never increased past 15.2A, but in the past, it's charged up to a full 20A.

The battery itself will control the current. You can offer whatever amps you want, but don’t offer more than it can handle. The battery will decide how many amps it can take. Since your battery was already mostly full at 89%, that’s likely why it was limiting current. It can’t handle too much current as it gets closer to being full. True for most any battery, lead acid or lithium.

 

[wme]

FWIW, I am the electrical category of "enough knowledge to be dangerous". I have a pair of the 100ah LFP's in my RV, they are in the winter storage mode in my heated garage. In spring time I charge them in parallel with a 10 amp adjustable v power supply. I set the PS to 14.2v and leave it hooked up for several days. My theory is matched top balance. What really happens, I have no idea.